Site Analysis

Site: Anna District, Tainan

Tainan is a typical coastal city as many others in Asia, such as Bangkok, Tokyo, Jakarta, Mumbai. They are rapidly expanding seaward and will vulnerable to flooding caused by sea-level rising and extreme weather in the future. Anna District is one of the particular areas where located on the border of Tainan city, and Anna District is believed to be the next developing area for extending Tainan city, according to the prediction from Space Syntax analysis development history. (Figure 5.14) It is predicted that many new communities will be constructed to provide more accommodation for (young) people flows from the city centre.

However, here will be the largest area covered by seawater in Taiwan if sea-level keep rising. Anna District also endures flooding very often in summer in recent decades. All of these site conditions cover most factors that cause flooding in Asia.

Anna District is a reclaimed land formed 200 years ago, along with the inundation of Zengwen River. (Figure 5.15) Anna District was an inland sea. The coastline moved to the current position that followed with the inundation. The inland sea became lagoon first that the industry was still original fishing, then became many pounds for aquaculture and detention basin. Finally, the area became land for agriculture use. Conclusion the evolution history, the area, was formed from the river inundation, which means flooding is the original condition pattern, although it harms many community and ecology.

Figure 5.14 Boundary extension history of Tainan City

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1700 1700

1823 1871

1911 ALL

Figure 5.15 Waterways evolu-tion of Zeng-Wen River

The flooding history of the Zeng-Wen River shows the evolution of the waterways. The order follows the main significant flooding events in 1823, 1871, and 1911. Thematic Research | 126

Site Analysis

+1 m

+3 m +2 m

+4 m

+5 m +9 m

Figure 5.16 Sea-level rising influence area

Figure 5.17 Easily flooding Figure 5.18 Water facilities

Figure 5.19 Ground level Figure 5.20 Potential Risks of Soil Liquefaction

Figure 5.21 Soil Category Figure 5.22 Soil Quality

Easily flooding area

Figure 5.23 clearly shows that flooding mainly happens in the low-lying area, especially the site’s central community. The residential areas and the potential developing areas are the lowest in the site, which means water flows automatically and causes flooding. It is the main issue in the area. However, there are still some areas (blue circles) flooding caused by other reasons instead of ground level.

Figure 5.23 Ground Level - Easily Flooding Area

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